package com.nmgydy.util;

import java.security.MessageDigest;

public class SHA1Util {
	private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };    

	private static String getFormattedText(byte[] bytes) {    
		int len = bytes.length;    
		StringBuilder buf = new StringBuilder(len * 2);    
		// 把密文转换成十六进制的字符串形式    
		for (int j = 0; j < len; j++) {    
			buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);    
			buf.append(HEX_DIGITS[bytes[j] & 0x0f]);    
		}    
		return buf.toString();    
	}    

	public static String encode(String str) {    
		if (str == null) {    
			return null;    
		}    
		try {    
			MessageDigest messageDigest = MessageDigest.getInstance("SHA1");    
			messageDigest.update(str.getBytes());    
			return getFormattedText(messageDigest.digest());    
		} catch (Exception e) {    
			throw new RuntimeException(e);    
		}    
	}    
}
